Android Studio3.0 编译C++成so

本次只是简单记录下怎么使用Android Studio3.0 编译C++成so，以备以后查看。

1.打开AS新建一个项目，这里见NativeBuild，勾选Include C++ support：

2.在app/src/main下新建一个jniLibs，将opencv android-sdk的库文件(这里使用so)拷贝到该目录下

3.将自己的c++代码放在app/src/main/cpp下，这里将整个c++代码目录src拷贝到这里

4.修改app/CMakeList.txt,修改如下

# For more information about using CMake with Android Studio, read the
# documentation: https://d.android.com/studio/projects/add-native-code.html

# Sets the minimum version of CMake required to build the native library.

cmake_minimum_required(VERSION 3.4.1)
set(CMAKE_VERBOSE_MAKEFILE on)
# Creates and names a library, sets it as either STATIC
# or SHARED, and provides the relative paths to its source code.
# You can define multiple libraries, and CMake builds them for you.
# Gradle automatically packages shared libraries with your APK.

include_directories(src/main/cpp
                    src/main/cpp/include
                    src/main/cpp/bc_api
                    src/main/cpp/bc_fillbg
                    src/main/cpp/bc_intelligent_fill_background
                    src/main/cpp/bc_utility)

file(GLOB IMGPROC_SRCS
        src/main/cpp/bc_imgproc_jniapi.cpp
        src/main/cpp/src/bc_api/*.cpp
        src/main/cpp/src/bc_intelligent_fill_background/*.cpp
        src/main/cpp/src/bc_utility/*.cpp)

add_library(opencv_java3
             SHARED
             IMPORTED)
set_target_properties(# Specifies the target library.
                       opencv_java3
                       # Specifies the parameter you want to define
                       PROPERTIES IMPORTED_LOCATION
                        # Provides the path to the library you want to import
                       ${CMAKE_SOURCE_DIR}/src/main/jniLibs/${ANDROID_ABI}/libopencv_java3.so)

add_library(imgproc SHARED ${IMGPROC_SRCS})
message(STATUS "******************************${IMGPROC_SRCS}")
target_link_libraries(imgproc log android -ljnigraphics m opencv_java3)

add_library( # Sets the name of the library.
             native-lib

             # Sets the library as a shared library.
             SHARED

             # Provides a relative path to your source file(s).
             src/main/cpp/native-lib.cpp )

# Searches for a specified prebuilt library and stores the path as a
# variable. Because CMake includes system libraries in the search path by
# default, you only need to specify the name of the public NDK library
# you want to add. CMake verifies that the library exists before
# completing its build.

find_library( # Sets the name of the path variable.
              log-lib

              # Specifies the name of the NDK library that
              # you want CMake to locate.
              log )

# Specifies libraries CMake should link to your target library. You
# can link multiple libraries, such as libraries you define in this
# build script, prebuilt third-party libraries, or system libraries.

target_link_libraries( # Specifies the target library.
                       native-lib

                       # Links the target library to the log library
                       # included in the NDK.
                       ${log-lib} )

5.配置build.gradle

apply plugin: 'com.android.application'

android {
    compileSdkVersion 27
    defaultConfig {
        applicationId "ndkbuild.nativetest"
        minSdkVersion 21
        targetSdkVersion 27
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        externalNativeBuild {
            cmake {
                cppFlags "-std=c++11 -frtti -fexceptions"
            }
        }
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    externalNativeBuild {
        cmake {
            path "CMakeLists.txt"
        }
    }

    packagingOptions{
        doNotStrip '*/mips/*.so'
        doNotStrip '*/mips64/*.so'
    }
    sourceSets {
        main {
            jniLibs.srcDirs 'src/main/jniLibs'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:27.1.1'
    implementation 'com.android.support.constraint:constraint-layout:1.1.2'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
}

6.运行Make Project则生成对应的so